Our primary aimis to compare the strategy of PICA to CABG as a revascularization procedure for patients with severe symptomatic multivessel coronary artery disease. The primary endpoint will include nonfatal cardiac events and mortality observed in selected clinical patient subsets strattified by number of diseased vessels and ventricular function. Major secondary endpoints will include quality of life assessment and cost effectiveness of the initial strategy of PICA versus CABG. A patient registry will be developed for all patients who undergo coronary angiography. All patients with class III, IV angina, unstable angina, or continuing engina post infarction who have multivessel disease at coronary angiography will undergo careful review to determine eligibility for angioplasty and coronary bypass grafting. Eligible patinets will be randomized to either form of therapy. Six months following the revascularization procedure, an exercise thallium study will be performed to determine exercise capacity and to assess any residual myocardial ischemia. All randomized patients will be required to have an elective cardiac catheterization one year following revascularization therapy to assess degree of revascularization, restenosis rates, graft patency, and left ventricular function, unless the patient develops recurrent symptoms mandating earlier restudy. Assessment of left ventricular function will be performed by contrast ventriculography. The incidence of primary and secondary events after a minimum four year follow-up will be determined in both arms of the study, and patients will be analyzed by treatment assignment. St. Louis University has adequate facilities for performing the work. The principal investigators have over a decade of experience participating in and executing multicenter clinical trials. St. Louis University Hospital has 5 dedicated cardiac surgery suites and 4 dedicated cardiac catheterization laboratories with an average case load of approximately 640 coronary bypass operations and 2,300 cardiac catherterizations per year. From May 1983 to July 1986, 910 initial percutaneous transluminal coronary angioplasty procedures were performed; 41% were multilesion PICA procedures, 63% of patients were referred for class III, IV angina or unstable agniga, or continuing angina post infarction, and 59% of patients who underwent PICA in 1986 had multivessel coronary disease. There is strong support within the Division of Cardiology and the Department of Medicine, and we expect to meet recruitment goals of this study.